As one of the more expensive glass types on the market, fire-rated glass has proven itself as a worthwhile investment.
A fire protection system that’s always on standby, fire-rated glazing prevents fires from spreading and causing absolutely devastating damage to a building. It also extends evacuation times, allowing building occupants to escape to safety.
What goes into how much it costs per square foot? It’s more than just the amount of glass you’ll need for a project.
What Comprises the Fire-Rated Glazing’s Cost Per Square Foot
How much does fire-rated glass cost? The answer comes down to these three main factors:
Possibly the most significant factor in determining the cost of fire-rated glazing is its location in a building. Much of this cost is determined by building codes.
For example, some building codes call for 90-minute glass, instead of 20-minute glass, in stairwells. Not surprisingly, 90-minute glass is more pricey.
Of course, building codes vary from place to place, right down to the municipality level. Although the International Code Council has set the minimum building code regulations, they are only the minimum. Different jurisdictions can impose more stringent but not less-stringent rules.
Make sure your architect or project manager is up to speed on all building costs and incorporates those regulations into your project’s design. Failing to follow codes is expensive -- chances are a building inspector will cite your project and require you to replace the glass.
Fire-rated glass breaks down into two categories: fire-resistive and fire protective. While both do stand up to extreme heat, there are differences between the two and their applications.
Fire-resistive glass not only contains flame and smoke in a space but also limits radiant heat transference. In other words, this glass not only protects people from flames and smoke but also from exposure to a blaze’s heat as they pass by a fire.
It’s primarily used in -- and often required for -- egress points, such as a fire escapes, stairwells, or corridors.
Fire-protective glass is designed to compartmentalize fire and smoke. It’s meant to prevent a blaze from spreading and causing more damage to a building. It doesn’t, however, block radiant and conductive heat.
It’s often used in steel fireproof doors and entrance sidelights.
In commercial or public spaces where glass is a predominant architectural feature, such as a hospital or hotel, fire-rated glass may need to be shaped for intricate spaces. This means a commercial glass manufacturer spends more time and labor to create a piece that fits where it’s supposed to.
Is There a Substitute for Fire-Rated Glazing?
Technically, yes, there is a substitute for fire-rated glass -- a combination of tempered glass and a sprinkler system.
But tempered glass has its downfalls in fire protection:
- Though one of the strongest glasses on the market, it’s extremely sensitive to thermal stress and uneven heating and cooling. A small imperfection can cause it to break spontaneously, especially when exposed to extreme heat.
- Tempered glass is not made specifically to stand up to a blaze, meaning it’s not installed with containing a fire in mind. This impacts the safety of the space where you install this glass.
While tempered glass can be used to slow a fire down, it does not provide the same level of protection or peace of mind as fire-rated glass.
Why Use Fire-Rated Glazing?
Put simply, fire-rated glass is specifically manufactured to contain fires and keep people and property inside a building safe in a way traditional glass doesn’t. Insurance companies recognize this, too, and offer lower premiums for buildings with fire-rated glass.
Despite its up-front costs, the value of a protection system designed specifically for fires far outweighs those associated with recovering from a devastating blaze.
Considering fire-rated glass for your project?
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(Editor's note: This article was originally published in September 2020 and was recently updated.)